Linear Technology Corp. recently announced the LTC4234, a 20A Hot Swap controller with integrated MOSFET and current sensing, which provides a small footprint hot-plug solution for high-density circuit boards. The LTC4234 ensures safe board insertion and removal from live 2.9-to-15-V backplanes by controlling an internal N-channel power MOSFET to gently power up bulk capacitors and avoid sparks, connector damage and system glitches. By integrating the two most critical and largest Hot Swap components-power MOSFET and sense resistor, the LTC4234 reduces design time and saves board area. The internal, production-tested MOSFET’s safe operating area (SOA) is specified to ensure a rugged hot-plug solution, especially for space-constrained boards and cards in servers, network routers and switches, solid-state drives, and industrial systems.
Upon insertion, the LTC4234 waits for connector contact bounce to finish before soft-starting the output. A ground-referenced signal proportional to the load current is provided for monitoring with an external analog-to-digital converter (ADC). The current limit can be reduced from its 22.5A default with a single resistor, affording quick adjustment for dynamic load changes and various applications. For higher current applications, two LTC4234s are easily paralleled for a 40A solution. During overcurrent conditions, the controller limits MOSFET power dissipation by folding back its current limit for an adjustable timeout period. Undervoltage and overvoltage thresholds protect downstream loads against voltages outside a valid window, preventing circuit malfunction and damage.
The LTC4234’s features:
- Enables safe board insertion
- Integrated 4-mΩ MOSFET with sense resistor
- Guaranteed safe operating area
- Wide operating voltage range of 2.9 to 15 V
- Current limit for overcurrent fault protection
- Current and temperature monitor, power good & fault outputs
- –40°C to 125°C Operating temperature range
- 38-Pin 5 mm × 9 mm QFN Ppackage
The LTC4234 starts at $4.95 each in 1,000-piece quantities. Device samples and evaluation circuit boards are available online or from your local Linear Technology sales office.
Source: Linear Technology
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